I learned long time ago that using pop rivets, blind or not, don't make for
a good electrical connection. For all antennas, using aluminum tubing, I've
used self tapping screws for the last 30 yrs and it's served me well. It's
also much easier to take antennas apart and put them together again using
screws. As always, OMHO!
73 Bert, VE3NR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Roger
(K8RI) on TT
Sent: Monday, March 07, 2016 11:53 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] F12 C19XR Rivets
Good advise Jim,
My C19XR uses 3 rivets in a row at each element joint. I understand
that they may have gone to 6 using two sets of 3 opposing rivets.
That's the way I plan on repairing the ends of the 20 m reflector.
IIRC it does use larger rivets in the boom, but I don't remember the
size as I had forgotten the size for the elements..
After tomorrow (63F and 55 F for a low, 59/43 and near an inch of rain
Wed) The snow should be gone giving me easy access, if a bit squishy, to
the antenna.
These are what are called a "Blind Rivets" in that, unlike regular pop
rivets which have the mandril go all the way through, the end of the
rivet is solid to prevent water from leaking through, much like the
"Cherry Rivets" used in aircraft. The "Sonex" little single seater has
all riveted joints using these "Cherry rivets" instead of the typical
flush rivets requiring a bucking bar.
As Jim says, do not tap rivets in by taping on the mandril. Usually you
only forget once as the mandrel may just fall in and you no longer have
a blind rivet that may be a bit difficult to remove. Trying to drill
out a failed rivet can be frustrating as they often just spin in the
hole instead of holding for the drill bit to cut metal.
73 es thanks Jim
Roger (K8RI)
On 3/7/2016 Monday 10:54 PM, Jim Thomson wrote:
> Date: Sun, 6 Mar 2016 19:39:29 -0500
> From: Larry <lknain@nc.rr.com>
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] F12 C19XR Rivets
> Message-ID: <56DCCDC1.2020308@nc.rr.com>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> In the early days C3, EF 180B, and 240 generally used 0.125 inch rivets
> on the elements. The 180B had some 0.25 inch rivets as well if I recall.
> Booms used 0.25 inch rivets. The C3, for example, generally had 3 rivets
> per joint in the elements. I don't know how different the XR series is.
>
> 73, Larry W6NWS
>
> ## on my F-12 340N, 520, 615, EF-180B, and F12 shorty 44 foot 40m yagi,
all the rivets
> are .125, aluminum, and slightly domed heads, with steel mandrels. The
shorty 40m
> els used longer .125" rivets on the inboard portions only, where they are
triple walled.
>
> ## The EF-180B used .1875 rivets on the else.... but only in one
place.... like that huge swedge.
> All the booms used .1875 rivets on the factory end of each
splice...where as the end user
> portion of each boom splice used 1/4-20 SS bolts + nylocks.
>
> ## No .25 rivets were used any where. Although those small hand
riveters will pull a .1875
> rivet, they are very tough to pull. I bought a larger, looks like hedge
shears, type of riveter,
> made by pop company, aprx 25 inches long, to do the .1875 rivets. The
same longer riveter will also do
> .25 rivets, and also .125 rivets. But the big riveter is too awkward
for the .125 rivets, the small hand
> riveter is better for that job.
>
> ## POP co also makes a hand riveter, that uses 90 psi from ur
compressor, to pull any size of rivet, it also
> has an optional device to collect all the spent mandrels.
>
> ## DON'T put any anti oxidant grease on any rivets.... only the els
overlaps. Install ALL the rivets at any
> joint before you pull any rivets. IE: install 3 x rivets in a row,
then pull them one at a time. And if rivets 2+ 3
> start to back off, after pulling the 1st one, you have to tap the rivets
back in, so they are flush, b4 pulling them.
> Tap them back in via the domed heads..and NOT the mandrels.
>
> Jim VE7RF
>
> _______________________________________________
>
>
>
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--
73
Roger (K8RI)
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